Samsung boosts flash density with 3-bit, 32-layer design

Samsung Semiconductor continues to pack data more into solid-state storage, announcing Tuesday a new generation of its V-NAND technology that should help bring down the cost and power consumption of flash later this year.

The first 3-bit version of its 3D V-NAND (Vertical NAND) flash, it fits one more bit of data on each layer of the stacked technology. Bob Brennan, vice president of Samsung Semiconductor's memory solutions lab, expects an SSD (solid-state drive) using the new technology to ship by the end of this year.

V-NAND stacks flash vertically, achieving greater density without having to pack more components onto a single chip layer. Boosting density on flat, so-called planar chips is getting harder and more expensive because cells that are closer together have higher error rates. Without V-NAND, price declines on flash would slow down, Brennan said. This latest development should help to keep them going.

Samsung announced V-NAND with 24 layers a year ago and introduced a version with 32 layers earlier this year. It's already shipping SSDs made with 32-layer V-NAND, the 850 Pro line, which Samsung considers so durable it provides a 10-year warranty. Both of these V-NAND releases allowed for more data than planar flash in the same size chip, lowering cost per bit and opening up a new frontier to make storage more dense.

But those versions held just two bits of data per layer. Samsung has now fit three bits on each layer, achieving the equivalent of a 48-layer design, Brennan said. Samsung thinks it can keep adding layers, too, up to 90 or 100 at some point in the future. But adding more bits per layer is another way to increase density, one that's already familiar to flash vendors because it's been done in planar flash for years.

SSDs built with 3-bit V-NAND are likely to be used in a tier of flash storage intended for high capacity more than ultimate performance, Brennan said. Facebook has expressed interest in the cheap, 3-bit version of planar flash, called TLC (triple-level cell), for storing rarely accessed content such as photos.

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